The overall objective of this research effort is to determine whether cholesterol esters are an important source of the precursor acids for synthesis of prostaglandins and thromboxanes in adrenal cortical cells, and to investigate the role of these compounds in modifying or modulating the activity of adrenocosticotrophic hormone (ACTH) on these cells. The specific aims are: To verify the identity of the prostaglandins synthesized during incubation of dispersed adrenal cortical cells with arachidonic acid-1-14C in the presence and absence of ACTH. To determine the role of endogenous sterol esters in this tissue as a source of the arachidonate substrate for prostaglandin synthesis. To employ adrenal cortical cells from the tissue of normal rats and rats with essential fatty acid deficiency as an approach to determining the physiological role of endogenous prostaglandin synthesis on adrenal metabolism and steroidogenesis.